/*
 * Copyright (c) 2007 innoSysTec (R) GmbH, Germany. All rights reserved.
 * Original author: Edmund Wagner
 * Creation date: 31.05.2007
 *
 * Source: $HeadURL$
 * Last changed: $LastChangedDate$
 * 
 * the unrar licence applies to all junrar source and binary distributions 
 * you are not allowed to use this source to re-create the RAR compression algorithm
 * 
 * Here some html entities which can be used for escaping javadoc tags:
 * "&":  "&#038;" or "&amp;"
 * "<":  "&#060;" or "&lt;"
 * ">":  "&#062;" or "&gt;"
 * "@":  "&#064;" 
 */
package com.github.junrar.unpack.ppm;

import java.util.Arrays;

/**
 * DOCUMENT ME
 * 
 * @author $LastChangedBy$
 * @version $LastChangedRevision$
 */
public class SubAllocator {
	public static final int N1 = 4, N2 = 4, N3 = 4, N4 = (128 + 3 - 1 * N1 - 2
			* N2 - 3 * N3) / 4;

	public static final int N_INDEXES = N1 + N2 + N3 + N4;

	public static final int UNIT_SIZE = Math.max(PPMContext.size,
			RarMemBlock.size);

	public static final int FIXED_UNIT_SIZE = 12;

	private int subAllocatorSize;

	// byte Indx2Units[N_INDEXES], Units2Indx[128], GlueCount;
	private int[] indx2Units = new int[N_INDEXES];
	private int[] units2Indx = new int[128];
	private int glueCount;

	// byte *HeapStart,*LoUnit, *HiUnit;
	private int heapStart, loUnit, hiUnit;

	private final RarNode[] freeList = new RarNode[N_INDEXES];

	// byte *pText, *UnitsStart,*HeapEnd,*FakeUnitsStart;
	private int pText, unitsStart, heapEnd, fakeUnitsStart;

	private byte[] heap;

	private int freeListPos;

	private int tempMemBlockPos;

	// Temp fields
	private RarNode tempRarNode = null;
	private RarMemBlock tempRarMemBlock1 = null;
	private RarMemBlock tempRarMemBlock2 = null;
	private RarMemBlock tempRarMemBlock3 = null;

	public SubAllocator() {
		clean();
	}

	public void clean() {
		subAllocatorSize = 0;
	}

	private void insertNode(int p/* rarnode ptr */, int indx) {
		RarNode temp = tempRarNode;
		temp.setAddress(p);
		temp.setNext(freeList[indx].getNext());
		freeList[indx].setNext(temp);
	}

	public void incPText() {
		pText++;
	}

	private int removeNode(int indx) {
		int retVal = freeList[indx].getNext();
		RarNode temp = tempRarNode;
		temp.setAddress(retVal);
		freeList[indx].setNext(temp.getNext());
		return retVal;
	}

	private int U2B(int NU) {
		return /* 8*NU+4*NU */UNIT_SIZE * NU;
	}

	/* memblockptr */
	private int MBPtr(int BasePtr, int Items) {
		return (BasePtr + U2B(Items));
	}

	private void splitBlock(int pv/* ptr */, int oldIndx, int newIndx) {
		int i, uDiff = indx2Units[oldIndx] - indx2Units[newIndx];
		int p = pv + U2B(indx2Units[newIndx]);
		if (indx2Units[i = units2Indx[uDiff - 1]] != uDiff) {
			insertNode(p, --i);
			p += U2B(i = indx2Units[i]);
			uDiff -= i;
		}
		insertNode(p, units2Indx[uDiff - 1]);
	}

	public void stopSubAllocator() {
		if (subAllocatorSize != 0) {
			subAllocatorSize = 0;
			heap = null;
			heapStart = 1;
			// rarfree(HeapStart);
			// Free temp fields
			tempRarNode = null;
			tempRarMemBlock1 = null;
			tempRarMemBlock2 = null;
			tempRarMemBlock3 = null;
		}
	}

	public int GetAllocatedMemory() {
		return subAllocatorSize;
	};

	public boolean startSubAllocator(int SASize) {
		int t = SASize << 20;
		if (subAllocatorSize == t) {
			return true;
		}
		stopSubAllocator();
		int allocSize = t / FIXED_UNIT_SIZE * UNIT_SIZE + UNIT_SIZE;

		// adding space for freelist (needed for poiters)
		// 1+ for null pointer
		int realAllocSize = 1 + allocSize + 4 * N_INDEXES;
		// adding space for an additional memblock
		tempMemBlockPos = realAllocSize;
		realAllocSize += RarMemBlock.size;

		heap = new byte[realAllocSize];
		heapStart = 1;
		heapEnd = heapStart + allocSize - UNIT_SIZE;
		subAllocatorSize = t;
		// Bug fixed
		freeListPos = heapStart + allocSize;
		assert (realAllocSize - tempMemBlockPos == RarMemBlock.size) : realAllocSize
				+ " " + tempMemBlockPos + " " + RarMemBlock.size;

		// Init freeList
		for (int i = 0, pos = freeListPos; i < freeList.length; i++, pos += RarNode.size) {
			freeList[i] = new RarNode(heap);
			freeList[i].setAddress(pos);
		}

		// Init temp fields
		tempRarNode = new RarNode(heap);
		tempRarMemBlock1 = new RarMemBlock(heap);
		tempRarMemBlock2 = new RarMemBlock(heap);
		tempRarMemBlock3 = new RarMemBlock(heap);

		return true;
	}

	private void glueFreeBlocks() {
		RarMemBlock s0 = tempRarMemBlock1;
		s0.setAddress(tempMemBlockPos);
		RarMemBlock p = tempRarMemBlock2;
		RarMemBlock p1 = tempRarMemBlock3;
		int i, k, sz;
		if (loUnit != hiUnit) {
			heap[loUnit] = 0;
		}
		for (i = 0, s0.setPrev(s0), s0.setNext(s0); i < N_INDEXES; i++) {
			while (freeList[i].getNext() != 0) {
				p.setAddress(removeNode(i));// =(RAR_MEM_BLK*)RemoveNode(i);
				p.insertAt(s0);// p->insertAt(&s0);
				p.setStamp(0xFFFF);// p->Stamp=0xFFFF;
				p.setNU(indx2Units[i]);// p->NU=Indx2Units[i];
			}
		}
		for (p.setAddress(s0.getNext()); p.getAddress() != s0.getAddress(); p
				.setAddress(p.getNext())) {
			// while ((p1=MBPtr(p,p->NU))->Stamp == 0xFFFF && int(p->NU)+p1->NU
			// < 0x10000)
			// Bug fixed
			p1.setAddress(MBPtr(p.getAddress(), p.getNU()));
			while (p1.getStamp() == 0xFFFF && p.getNU() + p1.getNU() < 0x10000) {
				p1.remove();
				p.setNU(p.getNU() + p1.getNU());// ->NU += p1->NU;
				p1.setAddress(MBPtr(p.getAddress(), p.getNU()));
			}
		}
		// while ((p=s0.next) != &s0)
		// Bug fixed
		p.setAddress(s0.getNext());
		while (p.getAddress() != s0.getAddress()) {
			for (p.remove(), sz = p.getNU(); sz > 128; sz -= 128, p
					.setAddress(MBPtr(p.getAddress(), 128))) {
				insertNode(p.getAddress(), N_INDEXES - 1);
			}
			if (indx2Units[i = units2Indx[sz - 1]] != sz) {
				k = sz - indx2Units[--i];
				insertNode(MBPtr(p.getAddress(), sz - k), k - 1);
			}
			insertNode(p.getAddress(), i);
			p.setAddress(s0.getNext());
		}
	}

	private int allocUnitsRare(int indx) {
		if (glueCount == 0) {
			glueCount = 255;
			glueFreeBlocks();
			if (freeList[indx].getNext() != 0) {
				return removeNode(indx);
			}
		}
		int i = indx;
		do {
			if (++i == N_INDEXES) {
				glueCount--;
				i = U2B(indx2Units[indx]);
				int j = FIXED_UNIT_SIZE * indx2Units[indx];
				if (fakeUnitsStart - pText > j) {
					fakeUnitsStart -= j;
					unitsStart -= i;
					return unitsStart;
				}
				return (0);
			}
		} while (freeList[i].getNext() == 0);
		int retVal = removeNode(i);
		splitBlock(retVal, i, indx);
		return retVal;
	}

	public int allocUnits(int NU) {
		int indx = units2Indx[NU - 1];
		if (freeList[indx].getNext() != 0) {
			return removeNode(indx);
		}
		int retVal = loUnit;
		loUnit += U2B(indx2Units[indx]);
		if (loUnit <= hiUnit) {
			return retVal;
		}
		loUnit -= U2B(indx2Units[indx]);
		return allocUnitsRare(indx);
	}

	public int allocContext() {
		if (hiUnit != loUnit)
			return (hiUnit -= UNIT_SIZE);
		if (freeList[0].getNext() != 0) {
			return removeNode(0);
		}
		return allocUnitsRare(0);
	}

	public int expandUnits(int oldPtr, int OldNU) {
		int i0 = units2Indx[OldNU - 1];
		int i1 = units2Indx[OldNU - 1 + 1];
		if (i0 == i1) {
			return oldPtr;
		}
		int ptr = allocUnits(OldNU + 1);
		if (ptr != 0) {
			// memcpy(ptr,OldPtr,U2B(OldNU));
			System.arraycopy(heap, oldPtr, heap, ptr, U2B(OldNU));
			insertNode(oldPtr, i0);
		}
		return ptr;
	}

	public int shrinkUnits(int oldPtr, int oldNU, int newNU) {
		// System.out.println("SubAllocator.shrinkUnits(" + OldPtr + ", " +
		// OldNU + ", " + NewNU + ")");
		int i0 = units2Indx[oldNU - 1];
		int i1 = units2Indx[newNU - 1];
		if (i0 == i1) {
			return oldPtr;
		}
		if (freeList[i1].getNext() != 0) {
			int ptr = removeNode(i1);
			// memcpy(ptr,OldPtr,U2B(NewNU));
			// for (int i = 0; i < U2B(NewNU); i++) {
			// heap[ptr + i] = heap[OldPtr + i];
			// }
			System.arraycopy(heap, oldPtr, heap, ptr, U2B(newNU));
			insertNode(oldPtr, i0);
			return ptr;
		} else {
			splitBlock(oldPtr, i0, i1);
			return oldPtr;
		}
	}

	public void freeUnits(int ptr, int OldNU) {
		insertNode(ptr, units2Indx[OldNU - 1]);
	}

	public int getFakeUnitsStart() {
		return fakeUnitsStart;
	}

	public void setFakeUnitsStart(int fakeUnitsStart) {
		this.fakeUnitsStart = fakeUnitsStart;
	}

	public int getHeapEnd() {
		return heapEnd;
	}

	public int getPText() {
		return pText;
	}

	public void setPText(int text) {
		pText = text;
	}

	public void decPText(int dPText) {
		setPText(getPText() - dPText);
	}

	public int getUnitsStart() {
		return unitsStart;
	}

	public void setUnitsStart(int unitsStart) {
		this.unitsStart = unitsStart;
	}

	public void initSubAllocator() {
		int i, k;
		Arrays.fill(heap, freeListPos, freeListPos + sizeOfFreeList(), (byte) 0);

		pText = heapStart;

		int size2 = FIXED_UNIT_SIZE
				* (subAllocatorSize / 8 / FIXED_UNIT_SIZE * 7);
		int realSize2 = size2 / FIXED_UNIT_SIZE * UNIT_SIZE;
		int size1 = subAllocatorSize - size2;
		int realSize1 = size1 / FIXED_UNIT_SIZE * UNIT_SIZE + size1
				% FIXED_UNIT_SIZE;
		hiUnit = heapStart + subAllocatorSize;
		loUnit = unitsStart = heapStart + realSize1;
		fakeUnitsStart = heapStart + size1;
		hiUnit = loUnit + realSize2;

		for (i = 0, k = 1; i < N1; i++, k += 1) {
			indx2Units[i] = k & 0xff;
		}
		for (k++; i < N1 + N2; i++, k += 2) {
			indx2Units[i] = k & 0xff;
		}
		for (k++; i < N1 + N2 + N3; i++, k += 3) {
			indx2Units[i] = k & 0xff;
		}
		for (k++; i < (N1 + N2 + N3 + N4); i++, k += 4) {
			indx2Units[i] = k & 0xff;
		}

		for (glueCount = 0, k = 0, i = 0; k < 128; k++) {
			i += ((indx2Units[i] < (k + 1)) ? 1 : 0);
			units2Indx[k] = i & 0xff;
		}

	}

	private int sizeOfFreeList() {
		return freeList.length * RarNode.size;
	}

	public byte[] getHeap() {
		return heap;
	}

	// Debug
	// public void dumpHeap() {
	// File file = new File("P:\\test\\heapdumpj");
	// OutputStream out = null;
	// try {
	// out = new FileOutputStream(file);
	// out.write(heap, heapStart, heapEnd - heapStart);
	// out.flush();
	// System.out.println("Heap dumped to " + file.getAbsolutePath());
	// }
	// catch (IOException e) {
	// e.printStackTrace();
	// }
	// finally {
	// FileUtil.close(out);
	// }
	// }

	// Debug
	@Override
	public String toString() {
		StringBuilder buffer = new StringBuilder();
		buffer.append("SubAllocator[");
		buffer.append("\n  subAllocatorSize=");
		buffer.append(subAllocatorSize);
		buffer.append("\n  glueCount=");
		buffer.append(glueCount);
		buffer.append("\n  heapStart=");
		buffer.append(heapStart);
		buffer.append("\n  loUnit=");
		buffer.append(loUnit);
		buffer.append("\n  hiUnit=");
		buffer.append(hiUnit);
		buffer.append("\n  pText=");
		buffer.append(pText);
		buffer.append("\n  unitsStart=");
		buffer.append(unitsStart);
		buffer.append("\n]");
		return buffer.toString();
	}

}
